Stringed musical instrument



Jan. 30, 1945. J w MCBRIDE STRINGED MUSICAL INSTRUMENT Filed March 16, 1942 2 Sheets-Sheet l .m R .Y 4 e E PM M N E Mm fm 0 m w R w M w W N \m .7 iv 4 I Jan. 30, 1945. J. w. M BRlDE STRINGED MUSICAL INSTRUMENT 2 Sheets-Sheet 2 Filed March 16, 1942 Patented Jan. 30, 1945 UNITED STATES PATENT OFFICE 2,368,256 STRINGED MUSICAL INSTRUMENT John W. McBride, Burbank, Calif. Application March 16, 1942, Serial No. 434,855

17 Claims.

This invention relates to a musical instrument, and especially to one having one or more tensioned strings, such as a guitar, mandolin, violin or the like.

This application is an improvement of two prior applications, both filed in the name of John W. McBride; one being entitled Stringed musical instrument, and flied on April 14, 1941, under Serial No. 388,379, which has matured into Patent No. 2,316,799, granted April 20, 1943; and the other being entitled Stringed musical instrumen, and filed on September 14, 1941, under Serial No. 410,813, which has matured into Patent No. 2,316,800, granted April 20, 1943.

In these prior applications, there are described mechanisms adapted to be operated by the fingers of a player, for determining the effective length of any of the strings, and thereby to determine the pitch of the sounds produced by the vibrating strings. The important part of the mechanisms therein described is a rod for each strin and rotatable about an axis havin generally the same direction as the string. Thi rod carries either a continuous or interrupted helical-like crest or its equivalent. The crest is adapted to contact the string directly; and the point of contact is determined by the angular position of the rod. It is one of the objects of this invention to improve in general, the apparatus described in said prior applications.

It is another object of this invention to make it possible more readily to determine the exact position of the mechanism for producing the desired pitch. In order to accomplish this result, the stopping of the strings is accomplished by frets transverse to the strings and movable into or out of contact with the string. A number of appropriately spaced movable frets are associated with each string. The choice of the particular fret that moves into contact with the string, may

be determined, as in the prior applications, by the choice of angular position of a crested rod.

It is still another object of this invention to make it possible so to move any of the frets into contact with the string as to set up a ping or vibrations in the string. In this way, it is possible to play the instrument without the necessity of other-wise actuating the string, as by percussion, plucking or bowing, the impact of the fret serving to produce the vibration.

The mechanism for operating the frets, as heretofore stated, .may, in this form of the in-, vention, be an angularly adjustable crested rod,

although other mechanisms may be utilized.

That form of the invention utilizing an interone is just beyond, and the other just before, that position which would move the correspondin fret to its outermost limit of movement. This simultaneous stopping of the string by a pair of frets results in a stable position of the mechanism, which requires at least a little force to disturb. Accordingly the player senses this stable position and his control of the instrument is rendered easier. Of course, only oneof the two frets in engagement with the string is effective to determine its pitch; that is, the one that corresponds to the higher pitch.

Thi invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of several embodiments of. the invention. For this purpose there are shown a. few forms in the drawings accompanying and forming part of the present specification. These forms will now :be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to lbe taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a plan view of a guitar incorporating the invention;

Fig. 2 is an enlarged fragmentary sectional view taken along the plane 2 2 of Fig. 1, parts of the figure being broken away;

Figs. 3, 4 and 5 are sectional views taken along the correspondingly numbered planes of Fig. 2;

Fig. 6 is an enlarged fragmentary sectional,

view of the left hand end of the instrument as viewed in Fig. 1, and illustrating the means for determining the pitch of any of the strings;

Fig. 7 is an isometric view of one of the" keys used for operating the mechanism for determining the pitch of any string;

Fig. 8 is an enlarged fragmentary sectional view illustrating how the frets are urged into contact with the string; I

Fig. 9 is an enlarged sectional view, partly broken away, the plane of the section bein nor mal to that of Fig. 8 and illustrating a pair of frets that are adjacent each other and in string engaging position Fig. 10 is a fragmentary view of a crested rod that may be -used in lieu of the crested rod illustrated in the previous figures; and

, Fig. 11 is an end view of the rod illustrated in Fig. 10, taken in the direction of arrow ii.

In the present instance the stringed instrument is shown as a guitar, having a conventional body I from which projects a hollowed-out neck portion 2. This neck portion terminates (Figs. 1 and 2) with the peg board 3 that accommodates the tuning pegs 4. These tuning pegs 4 are arranged to tension the strings that extend longitudinally of the neck 2 and across the body i. In the pres ent instance there are four string elements, two of which, having reference numerals B and 6, are in the form of single strings and the other two, having reference characters I and 8, being made up of a pair of parallel strings (Figs. 3 and 4). However, the term "string as used hereinafter, applies as well to a plural as well as a single strin structure. There are six pegs 4 corresponding to the six individual strings that extend above the neck portion 2. Each of these strings at the right hand ends pass over bridge piece 9 and are anchored in the body i as by the aid of the Do s I0. Adjacent the left hand end of the instrument, as viewed in Figs. 1 and 2, the strings pass across notches ll (Figs. 2 and 6) formed in a member l2. This member I2 is attached to the peg board 3 by the aid of the flange l3 accommodated in an appropriate recess in the top of the board 3, and by the aid of the screws M which attach the flange 'l3 in the recess.

The body ll of the instrument is shown in this instance as adapted to be provided with approprlate electrical control apparatus for the control of tone and volume. Thus in g neral, recesses in the body may be provided to accommodate the volume control mechanism I! as well as the tone control mechanism It (Fig. 1). Since the present invention does not relate to these con trols, further description thereof is unnecessary.

The strings I, B, 'l and 8 are tuned as heretofore stated, by appropriate manipulation of the pegs i. The particular pitch of vibration of each of the strings is determined by controlling the free length of vibration. This is accomplished by the aid of movable frets, there being in this instance a set of frets for each string. Thus in Fig. 1 there are a series of frets indicated in general by the reference character I! adapted to cooperate with and engage the double string 8. A similar series I 8 of movable frets is adapted to cooperate with the double string 1. Likewise the series of movable frets l9 cooperate with the string 6; and the series of movable frets cooperate with the string 8. These movable frets are arranged below the-strings, and move transversely of the length of the string. As indicated most clearly in Fig- 1, there are twenty-four frets in each series, corresponding accurately in spacing with the required free lengths oi vibration of the strings 5, 8, I and 8.

The movable frets are all guided for transverse movement in a pair of spaced guide plates 2| and 22. These guide plates are spaced immediately below the strings and are supported in a manner now to be described.

The pper guide plate 2| is shown in Fig. 2 as having a left hand portion extending oventhe flat upper surface of extension 23, formed integrally with-the member l2. The member [[2 is fastened to the guide plate II as by the aid of the flat head screws 24 (Figs. 2, 3 and 6). These screws 24 pass through the extension 23 and thread into the longitudinally extending bars 2!, 2!, 21, 2|.

and 28. These bars have sides which define channels through which the strings extend. They also have top surfaces cooperating to form a rest [or the hand of the player. In this way the hand of the player in the process of manipulating the keys (hereinafter described) for determinin the pitch of the strings, is maintained out of contact with the strings 5, 8, 1 and 8. Furthermore, disposed in the spaces between these bars 25 to 29 inclusive are a series of felt pads 30 upon which the strings rest. These felt pads form damping means for ensuring against undesired string vibrations at the left hand portion of the instrument.

The right hand end of the upper guide plate 2! is shown as attached by the aid of the screws 3| to a shoulder 32 formed intermediate the body l and the cavity 33 of the neck portion 2.

The lower guide plate 22 is held in spaced relation to the upper guide plate 2! by the aid of a plurality of spacers 34, 35 and 36. Through these spacers pass the fastening screws 3! which may thread into the lower guide plate 22.

Each of the movable frets included in the sets i7, 18. I9 and 20, is urged resiliently in a direction away from the corresponding string 5, 8, 'l or ii. The manner in which this is accomplished is seen to best advantage by the aid of Figs. 8 and 9 which illustrate a pair of adjacent frets 38 and 39 cooperating in this instance with the string I. The fret structure illustrated in Figs. 8 and 9 is common to all of the other frets and therefore a description of the frets 38 and 39 is sufficient as a description of all of them.

The frets are of general rectangular cross section, sliding in corresponding rectangular slots or apertures in the upper and lower guide plates 2| and 22. Intermediate the upper and lower guide plates each fret carries a pin l0. As indicated most clearly in Fig. 9, the ends of the pins are formed as half-round projections to serve as rests for the lower end of the light compression spring 4!, which encircles the fret. The upper end of the spring is restrained by the lower surface of the upper plate 21. Its lower end, operating on the flat surfaces of the half-round ends of the pin 10, prevents inadvertent withdrawal of these pins 40. The springs thus urge the frets 38 and 3! downwardly until the pins 40 contact the upper surface of the lower guide plate 22, and out of contact with string 6. This position of the frets is illustrated clearly in Fig. 2. l

The frets however may be urged upwardly a'gainst the force of the springs 4| by the aid of a mechanism now to be described. This mechanism is in the form of a cam rod associated with each setof frets l1, l8, l9 or 20. Since these cam rods are identical, but one of them need be described in detail.

Thus in connection with the string 6 there is illustrated a cam rod 42. This cam rod carries a "plurality of crests or cams, a palrof which are illustrated by the reference characters 43 and H in Figs. 8 and 9. These crests are spaced along the rod 42 in conformity with the spacing of the frets in the set l8. These crests are shown in the form of steep cams, having high points adapted to cooperate with the pointed lower ends aseaese 3 rotated for this purpose, attention is invited again to Figs. 8 and 9. Adjacent cams or crests 43 and 44 can cooperate with the corresponding frets 38 and 39 so that concurrently both are raised sufiiciently to contact the string 3., We may assume that Fig. 8 is a section looking toward the neck end of the instrument; that is, in the same direction as the section, Fig. 3. Rod 42 is then urged resiliently, in a'manner to be hereinafter described, in a clockwise direction, and may be manipulated to turn in opposition to this resilient force, in a counter-clockwise direction. Upon urging of rod 42 in a counterclockwise direction, cam 44 has not quite reached the position where the'fret 39 is raised to its maximum height; and the cam 43 has just passed its maximum height position. By appropriate proportioning of the crests or cams and of the movable frets, this position can be such that both of the frets 33 and 39 are in contact with the string 6. Of course that fret 39 which determines the shorter string length is active to determine the pitch of the string.

Due to the fact that the adjacent frets 39 and 38 are in positions corresponding respectively to cam positions just prior to the maximum height of the fret, and just past the maximum height of the fret this position of the two frets 39 and 39 is stable. Thus the pointed end 45 of fret 39 acts against cam 44 to urge rod 42 in a clockwise direction, while the pointed end 45 of fret 38 acts against cam 43 to urge rod 42 in a counterclockwise direction. These opposing torques serve to stabilize the rod position. The player senses this stable position at the time he is manipulating the device for determining the angular position of the rod 42. A little force at least is required to disturb the stable position illustrated in Figs. 8 and 9.

The movement of the frets upwardly to contact the string with which the frets cooperate may be made as sudden as desired by appropriate manipulation; in this way a percussion effect is produced which sets the string into vibration without the necessity of plucking or otherwise manipulating the string. Accordingly it is possible to play the instrument by appropriate manipulation of the crested cam rods 42.

The cam rod 42 is mounted for rotation in a manner now to be described. Thus its right hand end as illustrated in Fig. 2 is provided with a reduced bearin extension 46. This extension is journaled in the wall 41 formed integrally with the spacer 36. The left hand end of the rod 42 is similarly journaled by the aid of the reduced extension 48 which is accommodated in the downwardly extending portion 49 of member I2. Since therod 42 is quite long, provisions are made for an intermediate bearing. Underneath the spacer 35 a bearing member 50 (Figs. 2 and is provided. This bearing member cooperates with a cap member 5|. Between the bearing member 50 and the cap member 5| are accommodated the reduced portions 52 of all of the crested rods.

The crested rod 42,-heretofore mentioned, is

* typical of the other crested rods 53, 54 and 55 cooperating respectively with the series of frets l1, I8 and 20. The bearing supports for these additional rods are similar to those just described for rod 42.

The manner in which these rotatable rods 53, 54, 42 and 55 may be angularly adjusted may best be described in connection with Figs. 1, 2, 3 and 6. As illustrated in said prior applications, means, such as gears and racks may be used for this purpose; but in the present instance such gears and racks are obviated. The left hand end of each of the rotatable crested rods is somewhat enlarged in diameter. Each of them is provided with a wrap-around spiral spring such as 56. The inner ends of each of these springs may be anchored to the corresponding crested rod as by the aid of the radial slot 51. The outer ends such as 62 (Figs. 3 and 6) are respectively anchored to the ends of manipulable keys 58, 59, 60 and El. These keys slide in a direction transverse to the strings 5, 6, I and 8 and are guided for this movement in a manner to be hereinafter described. It is sufficient for the present to note that the convolutions of the springs 56 are arranged in such manner that they tend to rotate the rods 53, 54, 42 and 55 in a clockwise direction as viewed in Fig. 3, and to urge the keys 5%, 59, 69 and 6! toward the right as viewed in Fig. 3. Accordingly urging of any one of the keys toward the left as viewed in Fig. 3, or downward as viewed in Fig. 1 will cause a corresponding angular movement of one of the rods 53, 54, 42 or 55, in a counter-clockwise direction.

Each of the keys is provided at its left hand extremity with a recess 63 into which the end 62 of the corresponding spiral spring may be engaged (Fig. '7) Furthermore, as illustrated most clearly in Fig. 2, these keys are each in dovetailing relation with the extension 23 of member l2. This member 23 at its lower side is purposely provided with dovetail channels for the guidance of these keys.

A limit is imposed upon the movement of the keys towardthe right. For example, use may be made of a stop pin 64 (Figs. 3 and 6) extending upwardly from the inner extremity of the keys. This stop pin 64 may cooperate with the bottom of the slot 65 cut in the lower edge of the member 23 as viewed in Fig. 6. In order to limit the inward movementof the keys 58, 59, 60 and BI, each of the keys may be provided with the pair of stops 66 that are arranged to cooperate with the upper edge of theguide member 23, as viewed in Fig. 6.

Each of the spiral springs 56 thus urges its corresponding key 58, 59, 60 or 6| to the extreme position illustrated in Figs. 1, 3 and 6. These'keys remain in that position unless they be urged inwardly bythe fingers of a player. In this extreme outward position, the strings 5, 6; I and 8 are maintained at a definite free length by the aid of the supplemental movable frets 61, 68, 89 and 19 illustrated in Fig. 4. These frets are in turn urged to the upward string contacting position by the crests H, I2, 13, 14 which have passed in a clockwise direction just beyond that position which would raise these frets to the maximum height. This position is a stable one, and definitely establishes the maximum free vibrating lengths of the strings 5, 6, 1 and 8. Upon the least movement of the keys 58, 59, 60 and 6| inwardly, these crests l l I2, '13 and 14 move toward the left as viewed in Fig. 4, and out of operative relationship with the movable frets 61, 68, 69 and Ill.

The upper guide plate 2| as shown most clearly in Figs. 3 and 6 has one of its edges turned downwardly to form the flange 15, providing an enclosure for the left hand portion of the instrument. This may be supplemented by the side walls 76 (Fig. 6) attached to flange 15.

In order to facilitate the setting of each of the keys 58, 59, 60 and BI to correspond to a definite pitch, each of these keys may be provided with a series of closely spaced transverse lines 11 (Figs. 6 and 7). These graduations are exposed adjacent the end 18 of the key. These graduation marks 11 are intended to cooperate with the corresponding edge 19 of the supporting member 23 (Fig. 3).

Since a small linear movement of any of the keys 58, 59, 60 or BI causes a correspondingly large variation in the pitch of the string, these lines H are spaced quite closely together. In order to facilitate the setting of the keys to the desired position, a magnifying lens 80 (Fig. 3) is shown in this instance as formed integral with the member 29. This lens overlies the edge 19 and may be in the form of a cylinder extending transversely across all of the keys 58, 59, 50 and GI. Conveniently the member 29 formed integrall with the lens 80 may be made of some transparent plastic or the like.

The cylindrical lens member 80 thus provides an enlarged image of the edge 19 and the graduation lines 11.

In the form of the invention just described, the rotatablerods 53, 54, I2 and 55 are shown as provided with a series of cam-like crests that form a discontinuous helical-like arrangement. It is not essential, however, that these crests be discontinuous. The rotatable rods may take the form illustrated in Figs. and 11. In this instance the rod 8| which is representative of all of the rotatable rods in the instrument, is shown as provided with a continuous helical-like crest 82. Asbefore, the angular position of the rod 8| determines which of the frets is moved into contacting position with the string. The arrangement may again be such that a 'pair of adjacent frets are urged substantially simultaneously into contact with the string, to lend stability to any angular setting of the rod.

What is claimed is:

1. In a stringed musical instrument having one or more strings, a movable member for controlling the pitch of a string, said member having a series of graduations for facilitating adjustment of said member, and a stationary magnifying lens through which the graduations may be viewed.

2. In a stringed musical instrument having one or more strings, a manipulable member for controlling the pitch ofa string, means. guiding said member for movement in a rectilinear direction, said member having a series of graduation lines transverse to the direction of movement, means providing a stationary edge cooperating with said lines, and a stationary magnifying lens adjacent said edge, through which lens the lines may be viewed.

3. In a stringed musical instrument having a plurality of tensioned strings, aplurality of manipulable members respectively for determining the pitch of the strings, and movable in parallel paths, each of said members having a series of graduation lines transverse to the direction of movement of the members, means providing a stationary edge cooperating with said lines, and.

the rod, the outer end of said spring being attached to said member, the said spring being wound and unwound on the rod as the reciprocable member is moved in one or the other direction. a

5; In a stringed musical instrument, a tensioned string, a plurality of frets movable into contact with the string and spaced along the length of the string, and means, cooperating with the frets and movable to cause any of the frets to engage the string, comprising a rotatable rod extending transversely of the frets, and having raised portions selectively operating the frets, said raised portions constituting crested cams,

" those portions operating on adjacent frets being so displaced angularly that both frets may be moved substantially simultaneously into contact with the string, while the highest parts of the two corresponding cams are displaced respectively on opposite sides of the string.

6. In a stringed musical instrument, a stensioned spring, a plurality of fret movable into contact with the string and spaced along the length of the string, and means, cooperating with the frets and movable to cause any of the frets to engage the string, comprising a rotatable rod extending transversely of the frets, and having raised portions selectively operating the frets, said raised portions constituting crested cams, those portions operating on adjacent frets being so displaced angularly that both frets may be moved substantially simultaneously into contact with the string, while the highest parts of the two corresponding cams are displaced respectively on opposite sides of the string, and resilientmeans urging said frets toward the raised portions.

7. In a stringed musical instrument, one or more tensioned strings, a guide plate disposed beneath the strings, a plurality of frets for each string and guided for movement in apertures in said plate and adapted to engage the strings, and means beneath the guide plate for selectively moving said frets toward the strings.

8. In a stringed musical instrumenhone or more tensioned strings, a guide plate disposed beneath the strings, a plurality of fret for each string and guided for movement in apertures in said plate and adapted to engage the strings, and rotatable cam rods, respectively for each string, and extending beneath the guide plate, for selectively operating said frets,

9. In a stringed musical instrument, one or more tensioned trings, a. pair of apertured plates "located below the strings, movable frets for each string guided in alined apertures in said plates, spring means between the plates and urging the frets away from the strings, and cam means beneath [the plates and operable to move the frets selectively into contact with the respective string.

10. In a stringed musical instrument, one or more tensioned strings, a pair of apertured plates located below the strings, movable frets for each string guided in alined apertures in said plates,

'spring'means between the plates and urging the whereby the frets can move into and out of contact with th string.

12. In a stringed musical instrument, a tensioned string, a plurality of independently movable frets spaced along the length of the string,

means for restraining the frets for movement in a direction transverse to the string whereby the frets can move into and out of contact with the string, and means movableto operate any of the frets.

13. In a stringed musical instrument, a ten- ,sioned string, a plurality of independently movmeans for restrainingthe frets for movement in a direction transverseto the string whereby the frets can move into and out of contact with the string, and means movable to operate any of the frets, comprising a rotatable rod extending transversely of the frets, and having raised portions selectively operating the frets, and means con tinuously urging the frets against said raised portions.

l5. In a stringed musical instrument, a tensioned string, a plurality of independently movable frets spaced alon'g the length of the string,

means for restraining the frets for movement in a direction transverse to the string whereby the frets can move into and out of contact with the string, and means movable to operate any of the frets, comprising. a rotatable rod extending transversely of the frets, and having raised portions selectively operating the frets, said raised portions forming a continuous, helical-like crest. 16. In a stringed musicalinstrument, a te sioned string, a plurality of independently movable frets spaced along the lengthof the string, means for restraining the frets for movement in a direction transverse to the string whereby the frets can move into and out of contact with the string, and means movable to operate any of the frets, comprising a rotatable rod extending transversely of the frets, and having raised portions selectively operating the frets, said raised portions forming a series of discontinuous crests angularly and axially displaced from'each other.

17. In a stringed musical instrument, a tensioned string, a plurality of independently movable frets 'spacedalong the length of the string, means for restraining the frets for movement, in a direction transverse to the string whereby the frets can move into and out of contact with the string, and means, co-operating with the frets, and movable to cause any'of the frets to'engage the string, said movable means having a series of raised fret operating projections, adjacent projections being so placed as to be capable of substantially simultaneously urging the corresponding frets into contact with the string.

JOHN W. MCBRIDE. 

